Protection of people against chemical and biological agents is very important and is very necessary in the present world environment. Functional protective clothing and equipment are required for many workers such as firefighter, police officers, medical workers, chemical and biological researchers, environmental health workers, pesticide handlers and soldiers. In order to contribute to the improvement and maintenance of the health and well-being of workers exposed to chemical substances and biological agents, there is a need to develop, for their safeguard, an effective, rapid, and safe decontamination technology applied to the functional clothing and equipment. Indeed, as protective clothing and equipment have to be decontaminated before they are, for example taken off to avoid the agents from being transferred to the skin or cloth underneath and taken to an unprotected area, there is a need to develop a composition which, when applied to a fabric, will show an enhanced protection against noxious warfare agents by adding a self-detoxifying catalytic effect in neutralizing the chemical and/or biological warfare agents present in the environment.
The protective clothing and equipment are expected to provide protection for the users against a variety of noxious agents without having a negative impact on the performance of the users. More particularly, the clothing and equipment have to maintain personal comfort and ensure safety.
In the field of chemical protection against chemical and/or biological warfare agents, the ideal protective fabric, membrane, clothing or equipment should be lightweight, breathable and should selectively block toxic agents. This approach relies, amongst other things, on the use of selectively permeable materials. Indeed, the selective permeable membranes or semi-selective permeable materials present different advantages compare to non-breathable product especially regarding comfort. Indeed, selective permeable materials are flexible, they possess characteristics that facilitate the transport of water vapor, they allow moisture to penetrate the materials to provide, for example, comfort to the wearer, and they block entry of chemical, biological noxious or harmful agents. The use of selectively permeable materials is well known in the art and is described, for example, in U.S. Pat. Nos. 4,943,475, 5,391,426, and 6,395,383, in European Patent Applications Nos. 1700620A2, and 06300223.2, and in Canadian Patent No. 2,501,146. Generally, selectively permeable materials that possess high water vapor transmission are hydrophilic polymers like polyethylenimine (PEI) or amine polymers combined with other polymer such as polyvinyl alcohol (PVOH), and polyvinyl alcohol co-ethylene. However, not all of these hydrophilic polymers show a high catalytic effect in neutralizing the chemical, biological, noxious or harmful agents, but combinations of such materials can be prepared to enhance chemical and biological neutralization.
Canadian Patent No. 2,501,146 and U.S. patent application Ser. No. 11/081,149 filed on Mar. 15, 2005 owned by Stedfast describe a composition which can act as a barrier against harmful or noxious agents when applied to a fabric or other solid support. The composition that shows enhanced resistance to water and laundering can better adhere to fabric or other solid supports and has enhanced water vapor permeability. This composition comprises from 5 to 80% by weight of a polyvinyl acetate polymer or copolymer, from 5 to 20% by weight of an aliphatic amine, from 0 to 20% by weight of a polyvinyl alcohol or copolymer thereof, from 0.1 to 10% by weight of a surfactant, from 0 to 5% by weight of one or more metal salts or metal oxides, from 0.1 to 10% by weight of an epoxy resin or of a cross-linking agent, from 0.5 to 10% by weight of a defoamer agent and from 10 to 90% by weight of water. However, this composition, while showing enhanced resistance to water and laundering and blocking efficiently the harmful or noxious agents, possesses a limited potential in neutralizing rapidly the noxious and harmful chemical and biological agents. Indeed, this composition does not provide to a membrane a self-detoxifying catalytic treatment to neutralize the noxious chemical and/or biological warfare agents present in the environment.
Therefore, there is a need to develop selectively permeable fabrics or even air permeable materials that offer an enhanced protection against noxious warfare agents by adding a catalytic effect to neutralize the harmful or noxious agents present in the environment at different level of relative humidity. This catalytic effect is performed, for example, by the hydrolysis of chemical warfare agents and to Toxic Industrials Chemicals (TIC's) compounds.
It is well known in the art that activated carbon is a form of carbon that has been processed to make it extremely porous and thus to have a very large surface area available for adsorption and filtration. Activated carbons are used primarily for purifying gases for adsorption, solvent recovery, or deodorization and as an antidote to certain poisons. More particularly, activated carbon can be used as a substrate to improve the adsorptive capacity for some noxious or harmful agents and has selective adsorption properties to different gas and chemicals. Also, carbon technology presents some advantage for comfort as it allows venting. However, protective garment based on activated carbon technologies, which allow air transfer, do not provide protection such as one describes in this invention. Indeed, carbon based technologies have a limited adsorption capacity and once a membrane, material or garment is saturated, the carbon is no longer a barrier to the harmful or noxious agents and, of course, there is no indication when occurs this lost of protection.
Therefore, there is a need to develop a composition which acts as a barrier to harmful and noxious warfare agents, has enhanced water vapor permeability and presents a catalytic effect in neutralizing the harmful and noxious agents at different relative humidity levels. The composition of the present invention when applied to a membrane, textiles woven, knit or tricot, material tents, shelters, tanks, canisters, filter media or garment presents an enhanced protection against chemical, biological noxious or harmful agents by allowing their neutralization and hydrolysis.